Method and apparatus for making transparent sheet material



Sept. 17, 1935. r, E. M. KRATZ ET AL 2,014,937

METHOD AND APPARATUSL FOR MAKING TRANSPARENT SHEET MATERIAL Filed Aug. 25, 1932 2 Sheets-Sheet 1` Sept 17, 1935.. E. M. KRA'rz Er AL 2,014,937

METHOD AND APPARATUS FOR MAKING TRANSPARENT SHEET MATERIAL Filed Aug/ '25, 1932 2 sheets-sheet 2 Y Patented Sept. 17, 1.935

METHOD AND APPARATUS FOR MAKING TRANSPARENT SHEET MATERIAL Edouard M; Kratz and Hermann Heckel, Gary, Ind., assignors, by mesne assignments, to Marbo Products Corporation, Chicago, Ill., a corporation of Delaware Application August 25,v 1932,' Serial No. 630,406

(ci. 11i-15) 16 Claims.

'I'his invention relates to a process and apparatus for making a transparent sheet material..

It has previously been suggested thatl it should be possible to make thin transparent sheet material using casein as the principal ingredient but insofar as w'e are aware, no practical method or apparatus for accomplishing this objective has ever been developed. Casein may be hardened by We have succeeded in perfecting a method and v apparatus for producing a thin, transparent; continuous sheet or web `of a casein-formaldehyde composition in which the sheet material is formed rapidly and in a continuous strip so that large rolls of athin, transparent, uniform product mayl `be obtained. Our product is a very'satisfactory 25. material for use in packaging various commodities, being an equivalent to the cellulose ester A or regenerated cellulose sheets so universally used for this purpose. When in the form of rolls, it

is well adapted for use on the ordinary autol matic packagingmachines which are used'for packing various commodities.

It is, therefore, anA object of our invention to provide a method-,by which a quick 'setting composition comprising casein and formaldehyde may be formed into thin, flexible sheets.

j It -is-a further object of our invention to 'pro-4 vide an apparatus for the manufacture of `such sheet material in which the steps of mixing the casein. and formaldehyde and forming the mixture into sheets are performed within such a short space of time that the setting of the composition takes place after the sheet has been formed.

Other and further objects of our invention will be apparent from the following specification and 45 the accompanying drawings. rj- On the drawings:

Figure 1 is acomposite view showing a side elevation of a portion vof -a transparent paper machine embodying my invention, and a dia- .grammatic'view of a proportioning pump used in connection therewith. f Figure 2 is a fragmentary sectional view taken along the line II-II of Figure 4. y

,Figure 3 is'a fragmentary'enlarged sectional view taken along the line III-III of Figure 4 showing the mechanism for spreading our caseinformaldehyde solution.

Figure 4 is an end elevational view of the portion of our machine shown inligure l.

ias shown on the drawings: l5

The reference numeral 5 denotes a pair of -upright channel beams forming a supporting frame of an end portion of a ltransparent paper machine embodying our invention. A casting belt Gitravels around an idler roll 1 and` under a large 10 rubber covered roller 8, at which point a coating of vcasein is applied to the outer surface of said belt in a manner to be described hereinafter. From this point said belt 6 travels upwardly,

.passing around a rollers and into a compart-.l

ment I0 which is heated `by any suitable means to set the sheet material by completing the chemical reaction between the ingredients of the coating composition. From this point, the casting belt, which now carries a smooth non-ilowing'and 20 transparent coating of the casein composition,

` passes'to` a festoon drying chamber (not shown) in which the sheet is completely dried. After the drying step is completed, the casein film is stripped oi oi the casting belt, after which the 25 said belt is returned to the idler roller 1 shown in Figure 1, and the cycle is repeated. The power for driving' casting belt 6 is appliedto said belt by means of a suction roll (not shown) This method of driving casting belts is disclosed in 30 Reissuev Patent No. 17,854.

Since duplicate parts occur atA each side of our device, like reference numerals will be used to refer to each of the duplicated parts. Our coating assembly is supported on the frame '5 by 35l brackets I I. 'I'he faces of said brackets are provided with dovetail grooves or gibways I8 which slidably engage dovetail members I1, provision being made for movement of the dovetail members Il, with respect to the brackets II. Racks 40 I5 are provided along the under sides of the inembers I1 which. engage pinions I4 mounted at each end of a shaft I3. A crank I6 is provided for Y Irotation of the shaft I3. vThis arrangement is particularly convenient for 4emergency use, such 45 as, for example, when some portion of the machine has broken down and it is desired tov instantly'stop the vcoating operation.

. Alongv the upper side of the rack l members I'I,

a second set of dovetail grooves or gibways I9 50 are provided, which engage dovetail members 24, provision being made for relative movement.

Screws 22 threadedly engage the dovetail members 24 and extend through the upper portions of rack members vI,I.Lengthwise Vmovement of collars 2| and 23. Hand wheels 20 are provided for convenience in turning screws 22. Hand wheel 20 has been shown on the lefthand side only of Figure 4, a detail of the parts directly behind said hand wheels being shown on the right hand side. The fine adjustment thus provided isused to adjust the distance between the roller 8 and a chromium plated roller 38, which is supported on the dovetail members 24 by bearings 18.

Roller 30 is mounted on a shaft 8| which extends beyond the bearing 10 at 82. Power to drive roller 38 is applied to said extension of shaft 8| in'any desired manner.

The speed of the roller 30 with respect to the casting belt 6 is very critical. The roller 30 should move at slightly greater speed than the casting belt for best results. The speed of roller 30 and the adjustment of the doctor blade 28 must be such that a small fillet of our composi-4 tion will accumulate at 83. This llet is essential in preventing the formation of bubbles Aand thin spots in the layer of composition applied to the casting belt.

Dovetail members 24 are provided with dovetail or gibway grooves along their upper surfaces which engage do"etail projections on the bottom of dovetail members 26, provision being made for relative movement. Screws 25 threadedly engage the dove'tail members 26 and pass through the upper portions of the dovetail members 24, lengthwise movement being prevented by collars 21 and 12.

A fountain 28, which is shown in detail in Figure 3, is of a special construction which is adapted ,for use with a casein-formaldehydesolution which sets after being mixed for but a few seconds. The fountain 28 is supported upon a shaft 3|, which is suitably journaled at its ends in the members 26. An angle plate 32 is rigidly attached to said shaft 3| by means of screws, one of which is shown at 33. A metal plate 34, which forms the bottom member of the fountain 28, is supported by the angle plate 32. The lower edge ,of said plate 34 contacts with the roll 38 along a line of contact indicated at 35. A series of counter weights 36 adjustably attached to arms extending from the angle plate 32 assist in maintaining ycontact at the point35.

A series of flexible tubes 31 extend through holes in the plate 34, and supply casein-formaldehyde solution to the upper surface of said plate. A plate 38 is adjustably positioned in spaced' relation to the openings of said tubes 31 by means of screws 38 and 48. A suitable dam of rubber or other packing material 4| is placed along the upper edge of the plate 38 whereby the liquid delivered by tubes 31 is prevented from flowing upwardly Jalong the upper surface of plate 34. Plates 42 are placed at the ends of the fountain 28 to prevent ythe escape of the casein-formaldehyde solution.

The doctor blade 28 is rigidly attached to the members 26 by means of a -tube 43. -zThis tube s casting belt.

screws 22 in rack members |1 is prevented by The casein solution is supplied by a proportioning pump, indicated diagrammatically in Figure 1 which comprises cylinders 51 and 58, one of which is for the formaldehyde solution and the other the casein. The intake ports 59 and 60 are connected to suitable reservoirs containing the respective solutions. The piston rods 6| and 62 are connected to a shaft 45 by means of connecting rods 61 and 68 and the adjustable cranks 63 and 64 which are provided with radial slots 10 as at 65 and 66. The stroke of each cylinder may be independently adjusted by varying the position of the attachment of rods 61 and 68 in the slots of their respective cranks. A pipe 46 is connected to cylinders 51 and 58 and to a mix- 15 ing device which consists of an outer case 80.,- containing a paddle wheel 15 attached to a shaft 16 which is rotated by any suitable source of power attached to a wheel 11. This mixing device .'s connected to the flexible tubes 31 through 20 a pipe 18. Thus itwill be seen that the pump may be adjusted to deliver a continuous stream of case-in and formaldehyde solutions mixed in any suitable proportions.

- In operation, the separate solutions of form- 25 aldehyde and casein are pumped by the proportionlng pump into the pipe 46. From pipe 46 the mixed solution enters theJ mixing device 41L From the mixing device 41, the 'mixture of casein and formaldehyde is conducted to the series of flexible tubes 31' which distribute it evenly along the entire length of the fountain 28. The mixture enters the fountain between the plates 34 and 38. The' mixture forms a small pond between said plates, finally running through the open space or orifice at 48 which is at the bottom of the pond. A supply accumulates at the point 48 where it contacts with the roller 38.

At this point, a thin lm of the coating materlal is formed upon the surface of the roll 36. This lm is carried upwardly by the rotation of the roll until it contacts with the doctor blade 29 which scrapes off any excess material to give a uniform thickness to the coating layer. This .15 uniform layer is now carried around to the point 58 at which the surface of the roll 3l) lightly contacts with the outside surface of the casting belt 6. At this point, the casting belt is traveling in the opposite direction from that of the 50 surface of the roll 38 so that the coating layer isy transferred from the surface of the roll 38 to the. surface of the casting belt. ,Extremely flne adjustment of the apparatus is required since it is essential that there be no appreciable scraping of the casting belt by lthe roll 38 but yet they must contact sufficiently to permit substantially all of the coating solution on the surface of the'roller 38 to be transferred to the L-shaped blocks of iron 54 are attached to the frame 5 and bearings 55 supporting the roller 8 slidably engage therewith. Screws 5| threadedly engage the bearings 55 and pass through holes in the L-shaped blocks 54, vertical move.- ment in said blocks being prevented by collars 56 and 61.

'I'his vertical adjustment of the cylinder 8 supplements the lateral adjustment of the cylinder 30 and the doctor blade 28, described above. For 70 best results, the cylinder 8 shouldbe covered with a layer of rubber or other similar material. Av scraper 53 constantly cleans the surface of the cylinder 30, preventing an accumulation of dirt (at the line of contact 36.

Thus it will be seen that we have provided a machine in which a quicksetting solution may be mixed and formed into sheets at a suilicient speed so that the setting occurs entirely after the material is formed inta a sheet of the desired thickness. A special feature of our machine is that thereare no reservoirs or other containers to hold our solution after mixing, and our machine is designed'at all points in such manner that the mixed solution is advanced at a uniform l rate, reaching the point where it is formed into a sheet a denite number of seconds after it is mixed. At no point in the fountain are there corners or, sharp angles-so placed that part of the solution may take a round about route-reaching the surface of theroller 30 after a longer period of timethan the other portions cf the same solution.

Another .distinct advantage of our machine is that it is adapted to handle solutions of a high viscosity. In this respectit differs from previous `devices which depended upon the viscosity of the solution to determine the thickness of the sheet and required thatth'e solution be very dilute when thin sheets were to be produced. In our apparatus, the solution may be very viscous and the thickness of the film will be determined by the space between the doctor blade 29 and the roll 30, independent of the viscosity of thev solution being used. i

The mixture of casein and formaldehyde used in this apparatus is not a part of the invention vclaimed herein but will be made the subject matter of a separate application. The formaldehyde solution comprises a 10% solution of formaldehyde in water while the casein solution comprises a purified casein which has been dissolved in an aqueous'alkali and the :pH of the solution subsequently adjusted. The casein solution should comprise about 1314% casein and 3.4% glycerine or other softening agent, the balance being water.

I tions are prepared in the manner disclosed above,

the proportioning pump should be adjusted to mix about 1 part of formaldehyde solution with 22 parts ofthe casein solution.

, We are aware that many changes may be made and numerous details of construction may be varied through a wide rangev without departing from the principles of thisinvention, and we, thereforeL do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

We claim ,as our invention:

1. In an apparatus for producing sheet material, means for mixing constituent ingredients to be formed into sheet material in predetermined proportions, a feed roller, means for distributing the mixed ingredients uniformly the length of said roller to form a coating thereon,

scraping means for regulating the thickness of said coating and means for maintaining said scraping means at a constant temperature.

2. In an apparatus for producing sheet material, arotatable feed roller, means fr applying a coating of a viscous sheet forming material thereto, doctor means adjustably positioned with f respect to said roller to' gauge the thickness of said coating, and means for maintaining s aid doctor meansfat a constant temperature.

3. In a dev-ice of the class described a pair of racks having pinions cooperating therewith, a feed roller, barsbcarrying bearings supporting said roller and slideably attached to the upper faces of said racks, means for maintaining said bars in any desired position along the face of When ourcasein and formaldehyde solu.

doctor blade and fountain in an operative posi- 5 tion relative to said roller and means for maintaining said supporting members in any desired position along the upper faces of said bars.

4. In a device of the class described, a cylinder and `a doctor blade cooperating therewith, said cylinder being rotatably mounted on horizontal rack members, pinions cooperating with said racks and mounted on a single shaft whereby the position of said cylinder may be adjusted laterally, dovetail grooves provided in vsaid rack members, dovetail members carrying. said doctor blade interlocking with said grooves and slideable therein whereby the position of said doctor blade with respect to said cylinder may be adjusted. b 5. In a lm forming apparatus, a fountain roll, a slidable carriage for said fountain roll, a doctor, a carriage for said doctor slidable on the fountain roll carriage, and means for adjusting said doctor relative to said. fountain roll.

6. In a film forming apparatus, a carrier belt, a fountain roll, a carriage' for said fountain roll, moans for sliding said carriage to adjust said fountain roll relative to said carrier belt, a doctor, .a carriage for said`doctor and means for sliding the doctors carriage to adjust the doctor relative to said fountain roll.

7, In a lm forming apparatus, a resilient roll, a carrier belt trained around said resilient roll, a fountain roll below said resilient roll, a carriage .for said fountain roll, means for sliding said carriage to adjust said fountain roll relative to said resilient roll and carrier belt, a. doctor, a carriage for said doctor slidable on the fountain roll carriage and means for sliding the doctor carriage relative to the fountain roll carriage. p

8. A film forming apparatus comprising, inA combination a trough, a fountain roll rotatable through said trough, a doctor above said trough in adjustable spaced relation from the periphery of the fountain roll, a resilient roller above said 45 fountain roll, al casting belt trained around said resilient roller in contact with said fountain roll,

. means for rotating saidv fountain roll and means for rotating said resilient roller to advance the casting belt in a direction opposite to the direction in which the surface ofthe fountain roll is rotated.

9. A lm forming mechanism comprising, in combination, a trough for containing a film forming solution, a fountain roll rotatable through said trough for picking up a, film of said solution on its periphery, a doctor in adjustable spaced relation from the periphery of said roll to gauge the thickness-.of the film thereon, a casting'belt adapted to pick up the gauged illm 60 on said fountain roll and means for advancing said belt in a surface direction opposite tothe direction in which the `periphery of the fountain roll is rotating so thatv the illm thereon Vis wiped oi by the belt.

10. The process of'vmaking transparentP sheet material which comprises picking up a film of sheet forming solution on a smooth rotating surface, doctoring said lm to a uniform gauge, contacting the doctored film with a carrier belt advancing in a direction opposite tothe direction in which the lm is traveling to wipe the film fromV the rotating surface onto the belt, allowing the Yiilrn to dry on the belt, and stripping the (resulting sheet from the belt.

11. A method of making sheet material from a quick setting film forming solution which comprises continually mixing flowing streams of the solution ingredients in predetermined proportions, immediately flowing the mixed solution against a revolving surface to deposit a film on said surface, uniformly gauging the thickness of said nlm, transferring said film to a carrier belt,

allowing the film to set on said belt and stripping the resulting sheet material from said belt.

12. A method of making a transparent casein sheet material which 'comprises continually mixing a flowing stream of an aqueous casein solution containing a softening agent with an aqueous solution of formaldehyde in the proper proportion to form a quick setting solution, immediately flowing the mixed solution against a revolving surface to deposit a nlm on said surface, uniformly gaugingthe thickness of said film, wiping off said film onto a carrier belt, allowing the film to set on the carrier belt and stripping the resulting casein sheet from said belt.

, 13. In a film forming apparatus having a fountain roll, a fountain comprising a shaft, an angle member secured to said shaft, a plate on one leg of said angle member extending toward said fountain roll, a weight on the other leg of y said angle member, means to slide said weight on said leg to rotate the shaft and move the plate into the desired contact with said fountain roller.

14. In a film-forming apparatus, a fountain roll, a pivotally mountedgplate extending across the width of said roll and adapted to have an edge thereof scrape thereagainst, a second plate carried by the first plate and placed thereabove in inclined relation to define an orifice disposed toward the fountain roll, and means to feed a nlm-forming solution between the plates fordischarge through the orifice onto the fountain roll.

l5. In a film-forming apparatus, a fountain roll, an apron extending across the width of said roll having an edge urged against the periphery thereof, a plate carried by said apron in spaced relation thereabove to define an orifice disposed toward the fountain roll, said orifice being spaced from the fountain roll, a dam between the back 1 edge of the plate and the apron to seal the space therebetween, a plurality of conduits to supply a film-forming solution between the apron and plateuniformly across the widthy thereof for discharge through. the orifice, whereby said disl5 charged solution forms a small pond at the edge of the apron for coating the fountain roll, a. doctor for gauging the rthickness of the coating on the fountain roll, and an endless carrier band urged against the fountain roll for receiving the 20 doctored coating therefrom.

16. Apparatus for making films from a quickf setting, film-forming solution, whichcomprises a conduit for the non-setting ingredients of the solution, a second conduit for the setting agent 25 of the solution, means to regulate the amount of flow through said conduits, a feed pipe for receiving the materials from said conduits, a mixing device in said -feed pipe to admix thoroughly the setting agent with the other ingredients, 9, fountain roll, andmeans for immediatelf coating the solution from the feed pipe onto the fountain roll.

EDOUARD M. KRATZ.

HERMANN HECKEL. 

